Pollination Biology of Jacaranda oxyphylla with an Emphasis on Staminode Function

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Surface Roughness and Bacterial Adherence to Resin Composites and Ceramics

Purpose: The aim of this study was to evaluate the surface roughness and the in vitro adherence of Streptococcus mutans to indirect aesthetic restorative materials that are uncoated with saliva.Materials and Methods: Four groups of restorative materials were evaluated according to material type: (1) microparticulate feldspathic ceramic; (2) leucite-reinforced feldspathic ceramic; (3) microhybrid resin composite and (4) microfilled resin composite. Twenty standardised samples of each material were produced. Roughness analysis (Ra, n = 10) was performed using a roughness analyser. Adhesion tests (n = 10) were carried out in 24-well plates; colony-forming units (CFU/mL) were evaluated. The mean values of roughness (mu m) and adherence (CFU/mL) for each group were subjected to an analysis of variance and a Tukey test.Results: The leucite-reinforced feldspathic ceramic was rougher and presented higher bacterial adherence than the microparticulate feldspathic ceramic. The resin composites were similar with regard to surface roughness and bacterial adherence.Conclusions: The microhybrid and microfilled resin composites were similar and the leucite-reinforced feldspathic ceramic was rougher and presented higher bacterial adherence than the microparticulate feldspathic ceramic.

Streptococcus mutans Biofilm Adhesion on Composite Resin Surfaces After Different Finishing and Polishing Techniques

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of the surface treatment of plain carbon fiber posts on the retention of the composite core: an in vitro evaluation

Foi avaliado o possível efeito de tratamentos superficiais em pinos de fibra de carbono lisos, quando comparados aos pinos serrilhados, na retenção à resina composta empregada na confecção de núcleos de preenchimento. Foram utilizados cinqüenta pinos de fibra de carbono, divididos em cinco grupos: os quatro primeiros grupos eram constituídos por pinos do tipo liso, cujas superfícies foram tratadas, e o último grupo por dez pinos do tipo serrilhado. Foram desenvolvidas matrizes de resina acrílica com um leito ajustado para conter o pino, com um alargamento na porção coronária para posterior preenchimento com resina composta. Após o tratamento superficial, todos os pinos receberam camadas de primer, foram secos e então ajustados à matriz de resina, colocando-se a resina composta autopolimerizável na porção coronária para um núcleo de preenchimento de 3 mm. As amostras foram submetidas a termociclagem e armazenadas em água destilada por uma semana. Os espécimes foram testados por meio de ensaios mecânicos de tração, à velocidade de 0,5 mm/min, até o deslocamento do conjunto ou a fratura da resina do núcleo. As conclusões foram as seguintes: a) o tratamento superficial nos grupos tratados por meio de jateamento (Grupo A), pontas diamantadas marcadoras de profundidade para facetas laminadas (Grupo C) e alteração da morfologia da extremidade coronária (Grupo D) conferiu aos pinos lisos valores de retenção comparáveis aos dos pinos serrilhados (Grupo E) nos ensaios de tração, porém sem diferença estatisticamente significativa entre estes grupos; b) os pinos tratados por meio de pontas diamantadas de granulação média (Grupo B) obtiveram valores de retenção menores que os demais grupos.

A Strain Gauge Analysis of Microstrain Induced by Various Splinting Methods and Acrylic Resin Types for Implant Impressions

Purpose: The aim of this study was to investigate the level of microstrain that is exerted during polymerization of acrylic resins used for splinting during implant impressions. Material and Methods: Two acrylic resins (GC Pattern Resin, Duralay II) and square transfer coping splinting methods were evaluated by means of strain gauge analysis. Two implants were embedded in a polyurethane block, and the abutments were positioned. Sixty specimens were prepared using two square transfer Copings that were rigidly connected to each other using the acrylic resins. The specimens were randomly divided into three groups of 20 each for the splinting methods: Method 1 was a one-piece method; in method 2, the splint was separated and reconnected after 17 minutes; and in method 3, the splint was separated and reconnected after 24 hours. In each group, half the specimens were splinted with GC Pattern Resin and the other half were splinted with Duralay II. Three microstrain measurements were performed by four strain gauges placed on the upper surface of the polyurethane blocks at 5 hours after resin polymerization for all groups. The data were analyzed statistically. Results: Both resin type and splinting method significantly affected microstrain. interaction terms were also significant. Method 1 in combination with Duralay II produced significantly higher microstrain (1,962.1 mu epsilon) than the other methods with this material (method 2: 241.1 mu epsilon; method 3: 181.5 mu epsilon). No significant difference was found between splinting methods in combination with GC Pattern Resin (method 1: 173.8 mu epsilon; method 2: 112.6 mu epsilon; method 3: 105.4 mu epsilon). Conclusions: Because of the high microstrain generated, Duralay II should not be used for one-piece acrylic resin splinting, and separation and reconnection are suggested. For GC Pattern Resin, variations in splinting methods did not significantly affect the microstrain created. Int J Oral Maxillofac Implants 2012;27:341-345

Bond Strength of Two Resin Cements on Dentin Using Different Cementation Strategies

Purpose:This study evaluated the microtensile bond strength of two resin cements to dentin either with their corresponding self-etching adhesives or employing the three-step etch-and-rinse technique. The null hypothesis was that the etch-and-rinse adhesive system would generate higher bond strengths than the self-etching adhesives.Materials and Methods:Thirty-two human molars were randomly divided into four groups (N = 32, n = 8/per group): G1) ED Primer self-etching adhesive + Panavia F; G2) All-Bond 2 etch-and-rinse adhesive + Panavia F; G3) Multilink primer A/B self-etching adhesive + Multilink resin cement; G4) All-Bond 2 + Multilink. After cementation of composite resin blocks (5 x 5 x 4 mm), the specimens were stored in water (37 degrees C, 24 hours), and sectioned to obtain beams (+/- 1 mm2 of adhesive area) to be submitted to microtensile test. The data were analyzed using 2-way analysis of variance and Tukey's test (alpha = 0.05).Results:Although the cement type did not significantly affect the results (p = 0.35), a significant effect of the adhesive system (p = 0.0001) was found on the bond strength results. Interaction terms were not significant (p = 0.88751). The etch-and-rinse adhesive provided significantly higher bond strength values (MPa) with both resin cements (G2: 34.4 +/- 10.6; G4: 33.0 +/- 8.9) compared to the self-etching adhesive systems (G1: 19.8 +/- 6.6; G3: 17.8 +/- 7.2) (p < 0.0001). Pretest failures were more frequent in the groups where self-etching systems were used.Conclusion:Although the cement type did not affect the results, there was a significant effect of changing the bonding strategy. The use of the three-step etch-and-rinse adhesive resulted in significantly higher bond strength for both resin cements on dentin.CLINICAL SIGNIFICANCEDual polymerized resin cements tested could deliver higher bond strength to dentin in combination with etch-and-rinse adhesive systems as opposed to their use in combination with self-etching adhesives.(J Esthet Restor Dent 22:262-269, 2010).

Screw Spreading: Technical Considerations and Case Report

The spreading system is an alternative technique to the Summers osteotome. The crest expansion technique is a less invasive procedure in which the facial wall expands after the medullary bone is compressed against the cortical wall. It improves the density of the maxillary bone, which allows for greater initial stability of implants. A specific screw instrument, the "spreader," achieved a controlled and standardized dilation of the bone horizontally. The use of spreaders to enhance the dental implant site is a highly predictable procedure. (Int J Periodontics Restorative Dent 2011;31:141-147.)

A retrospective look at esthetic resin composite and glass-ionomer Class III restorations: A 2-year clinical evaluation

Objective: A restorative material for Class III cavities must, besides being functional, be esthetically satisfactory, providing good working conditions and several shade and color options. A clinical evaluation was initiated to compare the suitability of resin composite and glass-ionomer cement materials for such restorations.Method and materials: Forty-two Class III conservative cavities, esthetically important because of facial extensions, were selected. Resin composite restorations were placed in 21 cavities, and the remaining 21 were restored with glass-ionomer cement. The following characteristics were studied: color or-esthetics, anatomic shape, surface texture, staining, marginal infiltration, dental plaque retention, and occurrence of fracture. After 24 months, the restorations were evaluated.Results: the only statistically significant difference between the resin composite and glass-ionomer cement restorations in the experimental period involved color or esthetics.Conclusion: Resin composites and glass-ionomer materials provide excellent functional and esthetic results in Class III cavities when properly indicated.

Effect of caries preventive measures directed to expectant mothers on caries experience in their children

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The Effectiveness of Low-Intensity Red Laser for Activating a Bleaching Gel and Its Effect in Temperature of the Bleaching Gel and the Dental Pulp

Statement of the Problem: The effectiveness of low-intensity red laser for activating a bleaching gel and its effect in pulp temperature was not investigated in dental literature. Purpose: The objective of this study was to assess the effectiveness of low-intensity red laser for activating a bleaching gel, as well as its effect in temperature of the bleaching gel and the dental pulp. Materials and Methods: Forty extracted bovine teeth were immersed in a solution of coffee 14 days for darkening. The initial colors were recorded by spectrophotometric analysis. The specimens were randomly distributed into two groups (N = 20): the control, which did not receive light and the experimental group that received light from an appliance fitted with three red light-emitting laser diodes (? = 660 nm). A green-colored, 35% H2O2based bleaching gel was applied for 30 minutes, and changed three times. After bleaching, the colors were again measured to obtain the L*a*b* values. Color variation was calculated (?E) and the data submitted to the non-paired t-test (5%). To assess temperature, 10 human incisors were prepared, in which one thermocouple was placed on the bleaching gel applied on the surface of the teeth and another inside the pulp chamber. Results: There was a significant difference between the groups (p = 0.016), and the experimental group presented a significantly higher mean variation (7.21 +/- 2.76) in comparison with the control group (5.37 +/- 1.76). There was an increase in pulp temperature, but it was not sufficient to cause damage to the pulp. Conclusion: Bleaching gel activation with low-intensity red laser was capable of increasing the effectiveness of bleaching treatment and did not increase pulp temperature to levels deleterious to the pulp. CLINICAL SIGNIFICANCE The application of a low-intensity red laser was effective for activating a bleaching gel with green dye, without any deleterious increases in pulpal temperature. (J Esthet Restor Dent 24:126134, 2012)

Solid-phase peptide synthesis in highly loaded conditions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Uso da FTIR na obtenção de resinas e na síntese de peptídeos em fase sólida

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Rugosidade e pigmentação superficial de materiais ionoméricos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Microdureza de resinas em função da cor e luz halógena

O objetivo desse trabalho foi avaliar a influência da intensidade da luz e cor de uma resina composta no grau de dureza Knoop. Corpos-de-prova foram confeccionados utilizando-se matrizes de poliéster envoltas por um anel de cobre, contendo uma cavidade padronizada de 6 mm de diâmetro por 2 mm de espessura. Estas cavidades foram preenchidas com resina composta selecionada, Fill Magic - Vigodent, com as cores A3, B3, C3, D3 e I, fotopolimerizadas através de um fotopolimerizador Elipar, calibrado para produzir 3 intensidades de luz diferentes: 450 mW/cm², 800 mW/cm² e uma intensidade de luz crescente de 100 a 800 mW/cm². Foram confeccionados 90 corpos-de-prova em que o tempo de exposição da resina à luz halógena foi de 40 s. As amostras foram armazenadas em tubos de ensaio com água destilada a 37 ± 1ºC. Após este período, foram realizados os testes de dureza Knoop na região de superfície e fundo. Os resultados mostraram que houve diferença estatística em relação a intensidade de luz, entretanto em relação a cor, não houve diferença estatística. Os autores concluíram que a cor do compósito não influencia a dureza Knoop e que a intensidade progressiva promoveu os melhores resultados de dureza Knoop.

Influência do método de síntese na obtenção de pós de Na2TiSiO5

Este trabalho apresenta um estudo sistemático sobre a síntese e caracterização de pós de Na2TiSiO5. Foram estudadas as propriedades estruturais e morfológicas dos pós por intermédio de difração de raios X, espectroscopia Raman e microscopia eletrônica de varredura. As amostras foram produzidas por meio de duas rotas sintéticas distintas baseadas em métodos tipo Pechini e submetidas a diferentes tratamentos térmicos. Medidas de espectroscopia Raman nas resinas poliméricas foram feitas visando verificar a influência das diferentes rotas utilizadas na síntese dos pós. Com os dados de difração de raios X foi feito um estudo da evolução das fases cristalográficas. A estrutura cristalina das amostras foi analisada por meio de refinamento Rietveld. Por fim, a morfologia dos compostos de Na2TiSiO5 foi examinada por microscopia eletrônica de varredura. Os resultados obtidos mostraram que é possível melhorar a qualidade das amostras de Na2TiSiO5 alterando-se a rota sintética utlizada.